What NOT to say to a war vet: "Hey, Where's your helmet?"

Yesterday after my hospital shift I walked through the double-door exit to sunshine. The fall wind, blowing leaves off trees, welcomed me with a hug. Let Freedom Ring!! I looked around at the happy people outside --everyone looks happy outside to me when I spend 15 hours in a hospital-- and walked to the bike rack. I spotted my blue trusty, locked and ready to ride. Right next to my bike stood a large, sweaty, black-haired gentleman with over-sized gym shorts and a cheap VA Vet t-shirt. Seeing as all people outside hospitals are happy, I asked in a non-threatening, jovial tone, "Hey, where's your helmet?" See below for edited dialouge:

Man in oversized shorts: "Who the f--- are you?"

Man in wimpy doctor clothes (me): "Oh, sorry man, I didn't know you were in a bad mood, just having a conversation."

He continued locking up his bike, ignoring my comment. So I apologized, again.

I quickly fumbled for my bike lock keys in my pocket as I felt dangerously close to this dude. And images of crazy veterans doing crazy post-discharge things kept playing in my head. And I was the victim of all the images. But before I could get my key in the lock he stood up and asked, "What unit are you in?"

Me: "What unit am I in?"

Man: "Yes, what UNIT are you in?"

I stared at him, blankly for a few seconds then said,

 "Um, the unit of the human race?"

Man: "Yea, the unit of f------."

Me: "Um, okay, but aren't you part of that unit?" (At this point you might not think that a wise thing to say to this huge, emotionally revved up dude, but I was not thinking)

He walked up into my face, raised his shoulders like a man ready to plow through the offensive line and cremate  the quarterback, and said, "I'm part of unit 504 of the fifth division, Whooohaa!" Then he walked away.

I stood. I stared. My arms stood straight as fence posts by my side. And the best part, my heart rate was a cool 49, like I was on sunset beach in Oahu. I was strangely calm. Honestly, I didn't think he would do much to me physically, and even if he did, I was in front of a hospital. So no worries.

A few says prior to this Anna wrote letters to soldiers as part of a church activity. She came home and asked, "So, what do you say to a soldier you've never met?" All I can tell her now is one thing she should never say: "Hey, where's your helmet?"